Having owned an optima s(u)x nearly a decade ago, loosing money unloading it, because it wouldn't drive straight, I am extremely sensitive to this.
That said, my experience with the stinger ('22 MY) is that it is sensitive to road imperfections. Steering in general is quite responsive (tiny inputs = big changes). Tire PSI plays a role in this too. Higher pressures amplify this effect. However, it's nowhere near as bad as the optima was, requiring constant corrections to keep it straight on a straight interstate.
Our '15 accord sedan was easier to keep straight, but it's steering had a larger ratio (more steering change needed for similar amount of correction).
Was this dealership visit supposed to be under warranty?